PURPOSE: To regulate a mounting position of a cylindrical component to a support and to facilitate mounting and removing of the component at a support hole by disposing a plurality of protrusions to be engaged on an outer periphery of a cylindrical body along an axial direction, and engaging any of stages with a peripheral edge of the hole.

CONSTITUTION: A support hole 13 of a printed board, a chassis, etc., for supporting a cylindrical body 11 of a cylindrical component 10 at a support 12 side has three engaging protrusions Z1, Z2, Z3 of the same shape at an inner peripheral edge at peripheral intervals α, β, γ. A diameter X of a concentric circle for connecting bore side edges of the protrusions Z1-Z3 is set larger than a diameter V of a cylindrical component 10, and a diameter Y of the hole 13 is formed larger than a diameter W including protrusions A1-A3, B1-B3 to be engaged of the component 10. Thus, mounting and removing of the component 10 including the protrusions A1-A3, B1-B3 to be engaged at the hole 13 can be facilitated.